My first Saint Bernard was in a humane society, a family adopted her and felt it didn't get along well with their poodle. However, since I have had Constance she has been nothing but an angel!
She gets along well with every other dog she has ever come in contact with (with the exception of her being too friendly so other dogs can get irritated if they are not well socialized).
I'm never getting another breed of dog, there are many great dogs but she is the sweetest most loving dog I have ever had or met for that matter. If you come near her she will lean on you instantly to be petted.
Having said that, I have had a couple of instances where we were walking and other dogs have ran up to me barking. On these occasions she has always positioned herself directly between me and the other dogs and barked lower and meaner than I have ever heard (seeing as how she almost NEVER barks).
All and all from my experience Saint Bernards are a loyal, loving, faithful and protective breed. Assuming a large dog, as they do get quite large, is for you, than I would highly recommend a Saint to anyone and everyone. 200000000 out of 10 hands down 🙂